﻿using Microsoft.VisualBasic;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleAlgorithms.Utils
{
    public class Numbers
    {
        public static int[] Primes =
        {
            2,3,5,7,11,13,29,31,37,41,43,53,59,61,67,71,73,79,83,89,97,
            101,103,107,109,127,137,139,149,151,157,163,167,173,179,181,191,193,197,199,
            211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,
            307,311,313,317,331,337,347,349,353,359,367,373,379,383,389,397,
            401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491,499,
            503,509,521,523,541,547,557,563,569,571,577,587,593,599,
            601,607,613,617,619,631,641,643,647,653,659,661,673,677,683,691,
            701,709,719,727,733,739,743,751,757,761,769,773,787,797,
            809,811,821,823,827,839,853,859,863,877,881,883,887,
            907,911,919,929,937,941,947,953,967,971,977,983,991,997,
            1009,1013,1019,1021,1031,1033,1039,1049,1051,1061,1063,1069,1087,1091,1093,1097,1103,
            1109,1117,1123,1129,1151,1153,1163,1171,1181,1187,1193,1201,1213,1217,1223,1229,1231,1237,
            1249,1259,1277,1279,1283,1289,1291,1297,1301,1303,1307,1319,1321,1327,1361,1367,1373,1381,
            1409,1423,1427,1429,1433,1439,1447,1451,1453,1459,1471,1481,1483,1487,1489,1493,1499,
            1511,1523,1531,1543,1549,1553,1559,1567,1571,1579,1583,1597,
            1601,1607,1609,1613,1619,1621,1627,1637,1643,1657,1663,1667,1669,1693,1699,
            1709,1721,1723,1733,1741,1747,1753,1759,1777,1783,1783,1789,
            1801,1811,1823,1831,1847,1861,1867,1871,1873,1877,1879,1889,
            1901,1907,1913,1931,1933,1949,1951,1973,1979,1987
        };

        /// <summary>
        /// 对输入自然数进行分解，返回所有的质因数。
        /// </summary>
        /// <param name="n">待分解的自然数。</param>
        /// <returns></returns>
        public static List<int> GetCommonDividers(int n)
        {
            int v = n;
            var list = new List<int>(); 
            if (v < 2)
                return list;
             
            for (int i = 0; i < Primes.Length; i++)
            {
                while (v >= Primes[i])
                {
                    if (v % Primes[i] != 0)
                        break;
                    list.Add(Primes[i]);
                    v /= Primes[i];
                }
            }


            return list;
        }
    }
}
